CHAPTER XI.

A COLLISION.

Although the two physicians were deeply interested in the question of
toxicology they could not forget their situation and its perils. The
craft had nearly completed its half mile to the mouth of the tributary
which it was intended to ascend, when the polemen, pausing for a
moment's rest, whispered that they heard the sound of paddles again.

"_There they are_!"

It was Jack Everson who uttered the exclamation, loud enough for all to
hear. He pointed down stream as he spoke, and every one perceived the
dreaded boat returning.

Although nearer at hand than before, it seemed to be following the
course of the river, and there was hope that it would again pass
without discovering the shrinking ones so near land.

When first observed the other boat was fifty yards out and not quite so
far down stream. Moving against the current its progress was slower
than before, but its advance was plainly perceptible. The craft of the
white people had lost the momentum imparted by the poling, and was now
controlled only by the current, which was so sluggish close to the land
that the motion was hardly noticeable.

The hopes of our friends steadily rose until the other boat was almost
directly abreast. It would seem that if the occupants intended
attacking they would have veered inward before this, but there could be